Banca de DEFESA: SUELLEN LAILA ROCHA SILVA

EMETINE'S ANTILEUCEMIC POTENTIAL STUDY IN ELIMINATE LEUKEMIA STEM CELLS FROM ACUTE MYELOID LEUKEMIA

Antitumor; Cytotoxicity; Acute myeloid leukemia; Emetine; NF-kB; Leukemic stem cells.

INTRODUCTION: Acute myeloid leukemia (AML) is a disease with a low 5-year survival rate. One of the reasons for this high mortality is the resistance of leukemic stem cells (CTLs) to conventional treatments, leading to disease recurrence. The NFκB signaling pathway is activated in AML CTLs, making it an attractive target for the elimination of these cells. Emetine (EMT), an antiparasitic used clinically, has been shown to inhibit NF-κB signaling. OBJECTIVE: To evaluate the antileukemic potential of emetine in eliminating AML LSCs in an in vitro and in vivo translational model using KG-1a cells. METHODOLOGY: Initially, EMT was tested on a panel of cancerous and non-cancerous cells to determine the IC50 and evaluate its cytotoxicity. Then, the presence and elimination of CTLs was identified by flow cytometry, using antibodies for CD34, CD38, CD13, CD33 and CD123. Assays to investigate the mechanism of action of the compound using the KG-1a strain were performed, including trypan blue exclusion assay, analysis of cell death pattern, expression of caspase-3 and PARP-1, activation of the NF-κB pathway, evaluation of the cell cycle, oxidative stress and mitochondrial depolarization. In addition, analyzes were performed by confocal microscopy, qPCR and in vivo assay using NSG mice. RESULTS: EMT showed cytotoxicity against all cancer lines tested, with an IC50 of 0.74 µM for the KG-1a. The compound also reduced the percentage of CD13, CD34, CD38 and CD123 positive cells. It was observed that EMT induced apoptotic cell death, increased the expression of active caspase-3 and PARP-1 cleavage, promoted mitochondrial depolarization, generation of reactive oxygen species and internucleosomal DNA fragmentation, in addition to inhibiting the expression of NF- κB. Of the 92 genes analyzed by qPCR, 54 were up-regulated and 5 were down-regulated by the compound. In the xenograft model, EMT treatment reduced the amount of leukemic cells in the bone marrow and blood of mice. CONCLUSION: EMT has shown to be a promising cytotoxic compound, able to eliminate AML LSCs in vitro and in vivo, inducing the expression of active caspase-3, cleavage of PARP-1, generation of reactive oxygen species, fragmentation of internucleosomal DNA and inhibition of NF-κB pathway in KG-1a cells.